Process for preparing high-quality low-salt low-potassium heavy sodium carbonate and ammonium chloride

Abstract

A process for preparing high-quality low-salt low-potassium heavy sodium carbonate and ammonium chloride through direct vapour calcine, washing impurities (sodium chloride and potassium sulfate) withcondensed water in high-temp condition, reaction to generate water, hydrating with sodium carbonate and hot-air drying includes preparing raw materials, carbonifying, solid-liquid separation, calcine, packing finished sodium carbonate, heat exchange of liquid crystallizing, filtering and packing finished ammonium chloride. Its advantages include short technologica route, simple equipment and low energy consumption.

Description

technical field [0001] The invention relates to a production process of soda ash and ammonium chloride, in particular to a process for directly calcining with low-pressure steam, washing impurity sodium chloride and potassium sulfate with condensed water under high temperature conditions, and reacting water to be directly hydrated with sodium carbonate to form carbonic acid monohydrate Sodium and dry with hot air to manufacture low-salt and low-potassium heavy soda ash and ammonium chloride process. Background technique [0002] At present, there are three methods for industrial production of heavy soda ash at home and abroad: solid-phase extrusion method, solid-phase hydration method, and liquid-phase hydration method. Light soda ash, then send the light soda ash to a hydration machine to make sodium carbonate monohydrate. Calcined and dried in a rotary calciner at 120-140°C to make heavy soda ash, or extruded into blocks by solid phase extrusion, crushed and sieved into h...

AI Technical Summary

Problems solved by technology

It has five defects: one is the process selection, the pressure is unreasonable, and its disadvantage is that CO 2 The gas is injected and suppressed to the carbonization tower, and the solid decomposition of the calciner produces a large amount of CO 2 In the heating process of the gas, the decomposed gas is not discharged in time to suppress the pressure, which is not conducive to the positive direction of the reaction from the principle of chemical reaction balance, and the chemical reaction speed is very slow, and the production cycle is long

The second is the formation process of anhydrous sodium carbonate: in the operation, the hot air is used to preheat to 140°C, the heat transfer coefficient of the steam to the air is small, and the heat transfer coefficient of the hot air to the materials and equipment is small, and the temperature must be raised to 140°C Requires a large amount of steam and blower power There is high energy consumption

The process choice is to transport CO under pressure 2 The gas needs to be maintained at 0.3-0.8Mpa, which increases the energy consumption of the steam. Third, the operation is primitive and the physical strength is high: the upper and lower sealing plates of this method require manpower to disassemble and assemble once each production, and the products in the furnace are all manually fed into the furnace. Digging materials, each production of a can needs to manually enter the furnace to dig materials

Digging working environment is harsh

Fourth, there are a lot of equipment, and the operation of blocking pipeline equipment

Fifth, a lot of CO is wasted 2 Gas: In the operation of this method, hot air is used to preheat to 140°C. When the sodium bicarbonate material is at 120°C, a large amount of sodium bicarbonate will be heated and a large amount of CO will be decomposed. 2 gas

Run away with the air, wasting CO 2 And need to supplement a large amount of CO 2 Increase raw material energy consumption of heavy soda ash products

Therefore, the process equipment of this method is difficult to realize industrialized large-scale production, and the consumption of raw materials is high and the energy consumption is large.

Images